Amir Jajarmi; Bahareh Emadzadeh; Rassoul Kadkhodaee
Abstract
Introduction: Carrageenans are a family of linear sulphated polysaccharides that have broad applications in the food sector and pharmaceutical industry. Based on the degree of sulphation (polyelectrolytes) in carrageenan, only Kappa and Iota carrageenan have the ability of forming a gel structure. The ...
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Introduction: Carrageenans are a family of linear sulphated polysaccharides that have broad applications in the food sector and pharmaceutical industry. Based on the degree of sulphation (polyelectrolytes) in carrageenan, only Kappa and Iota carrageenan have the ability of forming a gel structure. The mechanical characteristics of their gels, however, is affected by the polyelectrolyte nature of their chains. Iota and kappa carrageenan provide elastic soft gel and brittle rigid one, respectively, in the presence of calcium and potassium salts as their favored ions; while their mixture provides a broad range of structures with unique textures. The combination of these two biopolymers would result in a broad range of unique textures for different applications. The aim of this Study was to determine the effect of chain association (molecular association) on the textural properties of kappa- Iota carrageenan mixed gel. The texture of gels was investigated through the puncture test to determine some properties including hardness, toughness, deformability modulus, resilience, yield point, and proportional limit. In addition, the stress relaxation test was applied to evaluate the effect of the chain association formed in the network on the stress decay parameter.
Materials and Methods: A commercial Kappa-carrageenan, Genugel type, and Iota- carrageenan, Genuvisco type without further purification were purchased from CP Kelco (Lille Skensved, Denmark). Potassium chloride (KCl) and calcium chloride dihydrate (CaCl2•2H2O) of analytical grade were purchased from Merck company. The mixtures were prepared in 2:1, 1.5:1.5 and 1:2 ratios and the final concentration of 0.3% w/w biopolymer. Both calcium and potassium chloride were added using a strategy adopted for each salt for keeping the same ionic strength of molar concentrations of 2.5, 5 and 7 mmol in the biopolymer dispersions. The mechanical properties of the gels were investigated using an XT. T2 Texture Analyzer (Stable Micro Systems, Surrey, UK). Peltier system was utilized in adjusting the temperature at 4oC. The samples were equilibrated at least 10 min before performing the test. Crosshead speed was adjusted at 10 mm/min to a 12 mm depth (50% from total length) from the surface of the samples using a 1 mm diameter cylindrical aluminum probe for puncture test and a 2 mm/min crosshead speed using a 75 mm diameter cylindrical aluminum probe in 20% strain was applied for the stress relaxation test during 60 second time interval. Pleg and Normand equation was applied for the determination of viscoelastic properties of samples.
Result & discussion: Among different methods in the mechanical study of biopolymer gel, the puncture test is a promising method due to its ability in applying normal and shear forces on and into the structure simultaneously. In the presence of calcium and Potassium salts, the same pattern in the puncture curve was observed with increasing of ionic strength in the medium. According to the chain association formed as a result of the ion type, the pattern shows a transient from the elastic to the plastic deformation with different limits. The hardness as a parameter that indicates a composite biopolymer network resistance to break up, showed a higher value for the network containing Potassium salt. It would be due to the formed intra chain association in the system. For calcium salt, the results revealed a small variation in the hardness parameter with increasing the ionic strength. The area under the curve of stress- time is defined as toughness of the structure. The network formed by the intra chain association in the presence of potassium shows a free chain movement which leads to a plastic deformation with absorbing more energy before breaking the gel structure. Concerning the type of chain association, higher values of deformability modulus in the gels containing calcium salt is reasonable. Resilience, yield point and proportional limit are the characters related to the network homogeneity and bond stretching. In the networks with no depletion region, applying an external force to the body would lead to a uniform change in the initial state of the structure. In this kind of netwoks, the force distributed in the whole structure uniformly and local stress is not created. The chain movement as a result of bond stretching, causes a back stress occurance in the structure. When the primary stress is eliminated, the accumulated back stress will make the polymer to return to its original form. Interweaving the network by the intra chain association will result in a homogenous network formation and subsequently, to a higher parameter values in the linear region. The large deformation measurements were performed through the stress relaxation test to study the response of the structure during the interval times and to evaluate the viscoelastic properties of biopolymers network. Longer stress decay time was observed for the network developed in the presence of Potassium salt. The result obtained by studying the stress decay rate was in agreement with the properties observed from the evaluation of the linear region in the puncture test. On the other hand, the deformability modulus values conform to the result from hypothetical asymptotic level of the normalized relaxation parameter.
Fatemeh Rahmati; Arash Koocheki; Mehdi Varidi; Rassoul Kadkhodaee
Abstract
Introduction: Proteins are food ingredients with critical functional properties and participation in developing food products. So far, functional properties of several plant proteins such as pea, chickpea and lentil, groundnut, beach pea and bayberry have been investigated. Nowadays, there is an increasing ...
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Introduction: Proteins are food ingredients with critical functional properties and participation in developing food products. So far, functional properties of several plant proteins such as pea, chickpea and lentil, groundnut, beach pea and bayberry have been investigated. Nowadays, there is an increasing demand for plant proteins because they are available and inexpensive. Legume proteins are important plant protein sources. However, except for soy, due to the inadequate information about their structural and functional properties, they do not have appropriate application as functional ingredients in food products. Beans are a great source of nutrients such as protein, carbohydrate, dietary fiber, minerals and vitamins. Based on the several research reports, different dry beans have 15-25% protein and they are the second group of legume seeds, after soy, cultivated throughout the world. As mentioned earlier, insufficient information about structure of legume proteins is the main reason why they are unexploited in food industry. Therefore, the goal of this research was to evaluate the functional properties of proteins from three types of common bean (Speckled Sugar, Red Mexican and Great Northern bean). We also have attempted to evaluate the structure-function relation of these three sources of bean proteins because it is known that there is a direct relation between chemical conformation and the function of a protein which must be considered in food processing. Materials and methods: Protein of three types of common bean (Speckled Sugar, Red Mexican, and Great Northern) was extracted (pH 9, water flour 10:1). Afterwards, their physicochemical (including protein electrophoresis pattern, solubility, hydrophobicity), and functional properties (including emulsifying capacity, heat stability, gelation and foaming capacity) were evaluated to understand how bean protein structure influences its structure. Electrophoresis pattern was obtained based on 2 dimensions (pH and molecular weight). Protein solubility was evaluated by biuret method at pH range 3-9. ANS (8-anilino-1-naphthalenesulfonic acid) was used to measure surface hydrophobicity (pH 3-7).Emulsion samples (1% protein, 25% sunflower oil, pH 3-7) were produced, then emulsion capacity and emulsion heat stability (80°C for 30 min) were evaluated. Gelation of proteins was evaluated at protein concentration of 4-12% at different pH values (3-7). Foaming capacity (%) was measured as the difference between volume after and before whipping. Foam stability (%) was recorded during 90 minutes. Results and Discussion: Results showed that all proteins were rich in Phaseolin. In fact, this fraction was the major building fraction of all three bean proteins. Evaluation of solubility indicated that isoelectric point of three proteins was located at acidic pH range (pH 4.5). Results confirmed an indirect relation between protein solubility and hydrophobicity. All three protein isolates, similar to the other legumes protein, were more soluble at alkaline pH, while the highest surface hydrophobicity was observed at pH 3. Generally, Speckled Sugar bean protein had the most solubility, while Great Northern bean protein showed the highest surface hydrophobicity. Among three bean protein isolates, Speckled Sugar bean protein performed better as an emulsifier, whereas Great Northern bean protein formed gel at the lowest concentration (6% at pHs 3 and 7). In addition, foaming was higher at acidic pH (pH 3). Therefore, it was concluded that emulsifying capacity is mostly influenced by protein solubility, while gelation and foaming properties are affected by protein hydrophobicity. As the main consequence, the results achieved in this research confirmed that there is a direct relation between structure and the function of a protein. In fact, special structural properties are responsible for special functions.
Akram Arianfar; Fakhri Shahidi; Rassoul Kadkhodaee; Mehdi Varidi
Abstract
Introduction: Tea (Camellia sinensis), is the most widely beverage after water across the world. The most important chemical composition in tea is phenolic compounds (catechins) that have antioxidant and anticarcinogenic properties and are benefited for cardiovascular disease. There are two major kinds ...
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Introduction: Tea (Camellia sinensis), is the most widely beverage after water across the world. The most important chemical composition in tea is phenolic compounds (catechins) that have antioxidant and anticarcinogenic properties and are benefited for cardiovascular disease. There are two major kinds of tea, black tea and green tea. Green Tea, is originated in China and dates back to several thousand years ago. In the production of green tea, young leaves are rolled and oxidized to decreasing oxidation but in production of black tea, tea leaves are oxidized (fermented) for 90-120 min after rolling and then catechins are converted to complexe compounds (theaflavins and thearubigins). The conventional method for extraction of green tea polyphenols compounds are heating, boiling, cold and heathing refluxe extraction, with long extraction periods and low extraction efficiency. In this study 3 techniques for extraction of polyphenol compounds from Green tea leaves were investigated and compored together.The main objective of this study was to determine the effects of differrent extraction conditions, temperature ( 40, 60, 80 and 100° C), different time ( 15, 30, 45 and 60 min ), microwave power (300, 600 and 900 % ) and ultrasound amplitude (40, 60, 80 and 100 W) on Green tea polyphenol content and antioxidant activity in three methods including Heat Reflux Extraction(HRE), Microwave Assisted Extraction(MAE) and Ultasound Assisted Extraction(UAE).Materials and Methods: Dried green tea leaves (supplied from Lahijan (Iran))were grinded for increasing the contact surface area between the solvent and solute. 1 g of green tea was extracted with 100 mL of water at various methods, Heathing Reflux Extraction(HRE), Microwave Assisted Extraction(MAE), by microsynth laboratory system (Milestone-ACT-36-Rev01) at 50 Hz and output 2450 MHz with adjustable power output (100-1000 W), temperature 180° C and Ultrasound Assisted Extraction (UAE) in double jacket vessel by using a 25 kHz ultrasonic system (model VCX 750, Sonics & Materials, Inc., USA), at a maximum nominal power output of 750W. All measurements were carried out in triplicate. The results were analysed statistically using the minitab 16 Program to determine the average value and standard error. Variance analysis, with a significant level of α= 0.05% was performed to determine the effect of time, temperature, microwave power and ultrasound amplitude on polyphenols content and antioxidant activity. Total phenol were determined spectrophotometerically by Folin-Ciocalteu method at 765 nm )Hewlett- Packard spectrophotometer model 8452A, Rockville). The antioxidant activity evaluated with the DPPH test spectrophotometrically at 517 nm. Results and Discussion: These results showed that polyphenol content is increased with increasing the time, temperature, ultrasound amplitude and microwave power of extraction. By increasing temperature to 80°C , time to 45 min, ultrasound amplitude from 40 to 80 and microwave power from 300 to 600, polyphenol content and antioxidant activity was increased and after that was constant. These results showed that, H.R.E require long extraction time and have low efficiency. Polyphenol compounds are thermally unstable and maybe degredate in thermal processing. Also, the best method for extraction was MAE, because of higher yield, higher contents of pol-yphenol and shortend time and this method was very efficient in the extraction of polyphenl compounds. The efficiency of extraction by UAE method is higher than HRE and lower than MAE method. Conclusion: UAE method compared to HRE method is enhanced the extraction of polyphenol, facilating solvent peneteration and increase the product releasing from intracellular. This method agitated the solvent to material and increased the contact surface between material and solven, and peneteration of solvent in to the green tea leaves. UAE canbe carried out at a lower temperature than HRE and decreased thermal damage.
Nafiseh Vahedi; Mostafa Mazaheri Tehrani; Seyed Mohammad Ali Razavi; Rassoul Kadkhodaee
Abstract
Low-fat butter is water in oil emulsion comprising a continuous fat phase including butter, emulsifiers and colorants and also a dispersed aqueous phase including water, stabilizers and proteins. In this research, by using protein components especially full-fat soy flour, a product were produced which ...
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Low-fat butter is water in oil emulsion comprising a continuous fat phase including butter, emulsifiers and colorants and also a dispersed aqueous phase including water, stabilizers and proteins. In this research, by using protein components especially full-fat soy flour, a product were produced which has extreme similarity to ordinary butter and also has good organoleptic properties. Water : butter ratio, soy flour : sodium caseinate ratio and emulsifier content were the designed factors and their effects on sensory properties of low-fat butter such as softness, spreadability, crumbling, hardness, adhesiveness, cohesiveness, melting rate, mouth coating, gumminess, butter flavor, soy flavor and finally overall acceptance were evaluated. The Central Composite Design (CCD) and Response Surface Methodology (RSM) were employed as experimental design and statistical analysis. Based on final results, the optimum formulation for low-fat butter were: water : butter ratio as 1.03 (50% water and 48.5% butter), soy flour : sodium caseinate as 1.57 (5% soy flour and 3.2% sodium caseinate) and 0.66% emulsifier. Apart from good nutritional effects of final product due to high protein content and lower fat content, that was spreadable at low temperatures and also has plastic characteristics of butter at ambient condition.
Rassoul Kadkhodaee; Arash Koocheki; Seyed Mohammad Ali Razavi
Abstract
The effect of addition of Qodumeh shahri (Lepidium perfoliatum) seed gum on the emulsion properties were investigated in this study. L. perfoliatum seed gum with 0-0.6% (w/w) concentration was used together with 2% (w/w) WPC to emulsify 20% (w/w) corn oil. The emulsion was analyzed for emulsion stability, ...
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The effect of addition of Qodumeh shahri (Lepidium perfoliatum) seed gum on the emulsion properties were investigated in this study. L. perfoliatum seed gum with 0-0.6% (w/w) concentration was used together with 2% (w/w) WPC to emulsify 20% (w/w) corn oil. The emulsion was analyzed for emulsion stability, particle size, specific surface area, particle size distribution and rheological properties. The mean particle size of emulsion decreased by increase in Qodume shahri seed gum up to 0.2% (w/w). Further increase in gum concentration had no significant effect on mean particle size of emulsion. Moreover, increase in gum concentration had no significant effect on particle size distribution (span) and specific surface area (m²/ml) of the emulsions. The rheological data indicated that increase in gum concentration significantly affected the viscosity, consistency coefficient (k) and flow behavior index (n) of the emulsions. Viscosity and consistency coefficient increased by increasing gum concentration. However, the flow behavior index decreased by the increase in Qodume shahri gum concentration. The flow behaviors of emulsions containing gum were well predicted by Herschel–Bulkley model (R2 > 0.99). While, in absence of gum, emulsion Showed Newtonian behavior.
Rassoul Kadkhodaee; Masoud Najaf Najafi
Abstract
The effect of pH, different concentration of Tween 80 and calcium ion on the stability of limonene-in-water emulsions stabilized by various concentration of sodium caseinate (2, 5 and 10%) was evaluated. To this end, emulsions were prepared by ultrasound and their quality attributes including size distribution, ...
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The effect of pH, different concentration of Tween 80 and calcium ion on the stability of limonene-in-water emulsions stabilized by various concentration of sodium caseinate (2, 5 and 10%) was evaluated. To this end, emulsions were prepared by ultrasound and their quality attributes including size distribution, mean diameter of droplets, specific surface area and span number were studied as a result of the contribution of experimental parameters. The results showed that emulsions stabilized by 10% sodium caseinate had finer droplets with smaller span values as well as narrower and sharper size distribution curves compared to others. It was also found that by increasing the concentration of Tween 80 up to 1.5% the size of emulsion droplets and the span value decreased but increased afterwards. Moreover, pH and calcium ion significantly affected the diameter and specific surface area of droplets (p
Masoud Najaf Najafi; Rassoul Kadkhodaee
Abstract
Limonene is one of the widely used natural flavorings in the food industry. This compound has high volatility and sensitivity to oxidation and hence a significant portion of it is lost during processing and storage of foods. This work was, therefore, aimed at microencapsulating D-limonene by using freeze ...
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Limonene is one of the widely used natural flavorings in the food industry. This compound has high volatility and sensitivity to oxidation and hence a significant portion of it is lost during processing and storage of foods. This work was, therefore, aimed at microencapsulating D-limonene by using freeze drying. To this end, oil-in-water emulsions composing of 10% limonene (wall material basis) in an aqueous solution of 2, 5 and 10% sodium caseinate or modified starch (capsul) was prepared by ultrasound. The influence of the type and concentration of wall material on the properties of freeze-dried microcapsules such as percent of oil retention, surface oil content, encapsulation efficiency, moisture content and release rate of oil was evaluated. Comparison of microcapsules characteristics revealed that those made up with 10% modified starch could retain more limonene than those containing sodium caseinate or lower concentrations of modified starch with longer half-life over 6 weeks of storage at 25 °C.
Keywords: Microencapsulation, Sodium caseinate, Modified starch, Limonene, Freeze drying
Rassoul Kadkhodaee; Seyed Ali Mortazavi; Farideh Tabatabaei Yazdi
Abstract
The aim of this work was to investigate the influence of interactions between modified starch (Hi-Cap 100) and the nonionic surfactant Tween 80 on the properties of cardamom oil-in-water emulsion and its corresponding spray dried microcapsules. To this end the mean diameter and size distribution of droplets ...
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The aim of this work was to investigate the influence of interactions between modified starch (Hi-Cap 100) and the nonionic surfactant Tween 80 on the properties of cardamom oil-in-water emulsion and its corresponding spray dried microcapsules. To this end the mean diameter and size distribution of droplets as well as their polydispersity index and also the viscosity and flow behavior of emulsion samples along with the encapsulation efficiency of powders were determined in the presence of various ratios of Tween 80. The results showed that increasing the concentration of Tween 80 up to 1% decreased the size of droplets and their polydispersity index while further increase beyond this point led to adverse effect. Also significant rise in the viscosity and marked alteration in the flow behaviour of emulsions was observed within this limit, which clearly indicates the influence of Hi-Cap 100 and Tween 80 interaction on the quality attributes of samples. Moreover, the findings of this study demonstrated that the aforementioned interaction considerably affected the microstructure and overall encapsulation efficiency of spray dried powders.
Keywords: Emulsion, Microencapsulation, Surfactant, Modified starch, Hi-Cap 100, Tween 80
Elnaz Milani; Hashem Pourazerang; Rassoul Kadkhodaee; Haneh Vakilian; Shahrzad Vatankhah
Abstract
Inulin is widely distributed throughout the plant kingdom. It has been increasingly used in various foods due to its beneficial nutritional attributes as prebiotic ingredient. The Helianthus tuberosus could be a source of inulin, but scarce studies about its extraction exist. Ultrasound has attracted ...
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Inulin is widely distributed throughout the plant kingdom. It has been increasingly used in various foods due to its beneficial nutritional attributes as prebiotic ingredient. The Helianthus tuberosus could be a source of inulin, but scarce studies about its extraction exist. Ultrasound has attracted considerable interest in food science and technology due to its promising effects in food processing and preservation. The use of power ultrasound significantly improves the extraction of organic compounds contained within the body of plants and seeds. The mechanical effects of ultrasound provide a greater penetration of solvent into cellular materials and improve mass transfer. In some cases sonication increased the efficiency of extraction at lower temperatures producing a purer product in a shorter time. It seems that the application of ultrasound would be a promising method to enhance the extraction process. The objective of this study was to develop a set of optimum extraction conditions for Helianthus tuberosus with an aim towards improving inulin extraction yield. Experiment design employed central composite design (CCD) and response surface methodology (RSM). Determination of inulin content was measured with the difference between total carbohydrate and reducing sugars. Then, Inulin extraction yield (%) was calculated too. Based on canonical analysis, the optimal conditions for maximizing inulin extraction yield (91.26%) were at 45.95 °C for 31.44 min and amplitude of 100%.
Keywords: Inulin, Extraction, Helianthus Tuberosus, Ultrasonic technique
Rassoul Kadkhodaee; Seyed Ali Mortazavi
Abstract
In this study formation and properties of o/w emulsion stabilized by a mixture of sodium caseinate (2, 5 and 10 wt %) and non-ionic emulsifier Tween 80, sorbitan mono-9-octadecenoate, (0, 0.5, 1 and 1.5 wt %) were investigated at various pH values(3, 5 and 7) and calcium ion concentrations (0, 0.2, 0.4 ...
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In this study formation and properties of o/w emulsion stabilized by a mixture of sodium caseinate (2, 5 and 10 wt %) and non-ionic emulsifier Tween 80, sorbitan mono-9-octadecenoate, (0, 0.5, 1 and 1.5 wt %) were investigated at various pH values(3, 5 and 7) and calcium ion concentrations (0, 0.2, 0.4 and 0.6 wt%). Emulsion samples were prepared by using a sonicator with a nominal power output of 750 W and an operating frequency of 20 kHz. Sonication of samples was carried out in a temperature-controlled chamber at a constant temperature of 20 ºC and the highest acoustic power available for 3 minutes. The results showed that increasing the concentration of sodium caseinate and Tween 80 generally reduced the size of droplets, although it was observed that Tween80 adversely affected the size of droplets at higher concentration under acidic conditions. Moreover, pH and calcium ion significantly affected the diameter and specific surface area of droplets (p
